Technical Abstract:
The delineation of crop response zones to identify within-field areas where productivity varies with seasonal precipitation patterns can be used as an indicator of subsurface water flow, and is a first step towards delineating management zones for precision farming as a function of water availability. Spectral reflectance of crop canopies prior to harvest have been shown to be correlated with yield. Three years of yield monitor data comprising dramatically different climatic conditions were used to compute normalized difference yield indexes (NDYI) for examining crop spatial variability. The NDYI values and spatial patterns were found to be well correlated with airborne spectral data expressed as NDVI. The spatial patterns from the analysis are shown to be indicative of subsurface water flow pathways identified using a Ground Penetrating RADAR-Digital Elevation Model approach.